Lost all power need help

So I just bought a 1970 Duster 340. I took it out today for the first time since I purchased it and I lost all power. I got on it a little bit then everything shut off. I have no lights no nothing. What do you guys think the problem is? I think it might be the fusible link? This is my first classic car so I'm not really sure. Any help would be great. Thanks.

Check the fusable link for any "soft" spots... Then check the bulkhead connectors at the firewall both inside and outside to make sure that they did not loose their connection...